Zuzana Do\v sl\' a, PierLuigi Zezza
Quadratic functionals with a variable singular end point

Comment.Math.Univ.Carolinae 33,3 (1992) 411-425.

Abstract:In this paper we introduce the definition of coupled point with respect to a (scalar) quadratic functional on a noncompact interval. \par In terms of coupled points we prove necessary (and sufficient) conditions for the nonnegativity of these functionals.

Keywords: quadratic functional, singular quadratic functional, Euler-Lagrange equation, conjugate point, coupled point, singularity condition
AMS Subject Classification: 49B10, 34C10, 34A10